INDEX. 



471 



England, geological map of , explained, 

 10; index outline of, 371. 



Entreveines coal mine, 120. 



Equivalents, geological, the term ex- 

 plained, 151. 



Eruption of Cotopaxi, heard at the dis- 

 tance of 600 miles, 259. 



Escarpment, the steepest side of a moun- 

 tain, 51; generally on the side of a 

 mountain range nearest the sea, ib. 



Estuary 7iear Lewes, how filled up at no 

 distant period, 247. 



Et7ia, eruptions from, immense mass of, 

 257; eruptions of frequent, 258. 



Eupkemia ingulfed by an earthquake, 

 251. 



Euphotide. See Saussurite. 



Eurite, or white stone, a variety of gran- 

 ite in which felspar predominates, 58; 

 in its most compact form, becomes a 

 porphyry, ih. ; also called a compact 

 felspar, 65, 



External structure of rocks, 39. 



Extinct species of animals, probable mis- 

 takes respecting them, 333. 



Extraneous fossils. See Organic re- 

 mains. 



F. 



Fall of mountains, cause of, 315 ; of 

 Mont Grenier, 316; instances of, 318; 

 at Pleurs near Milan, 319. 



Faluns, or marls of the Loire, 244. 



Faults, or breaks, 105. See Dykes. 



Faulty ground in coal fields, 107. 



Felspar, or feldspar, less hard than 

 granite, 34; analyses of, 35; consti- 

 tutes the principal part of porphyries, 

 ih. ; liable to decompose from the pres- 

 ence of potash, ib. ; fusible without 

 the addition of alkalies, and forms 

 glass, 34. 



' porphyry of Cornwall, 65. 



FelspatJiic granite, in which felspar is 

 the principal ingredient, 58; called, 

 by Werner, white stone, ib. 



Fibrous, composed of long minute fi- 

 bres, 38. 



Fire clay, 104. 



dainp, 122. 



stone, or upper green sand, 201. 



Fish, thrown out during volcanic erup- 

 tions, 266. 



Fitton Dr., on the wealden, 191, 198. 



Flint, in and under chalk, its origin, 

 202; .a siliceous earth nearly pure, 

 203; flints often fall to pieces when 

 taken out of the chalk beds, ib. 



Flinty slate contains more silex than 

 common slate, 85 ; when it ceases to 

 have the slaty structure becomes 

 hornstone or petro-silex, ib. ; if it con- 

 tains crystals of felspar, becomes horn- 

 stone porphyry, ib. ; localities of, ib. 



Floetz, or parallel rocks of Werner, 

 83. 



Flour spar mine near Castleton, 288. 

 Flying Lizard, or pterodactyle, found 

 fossil, 24. 



Foliated, like thin leaves laid over each 



other, 39. 

 Folkstone marl, or gait, 201. 

 Fontainbleau sandstone, 231. 

 Footmarks in new red sandstone, 166-, 

 Forest marble, 185, 188. 

 Formations, geological, explained^ 



42. 



Fossils. See Organic remains. 



Fossil conchology, 29; observations on 

 the extent of its application to geolo- 

 gy, 343. 



Freestone. See Oolite. 



Freshwater formations, in the lakes of 

 North America, 216; in the Paris ba- 

 sin, 220; in the Isle of Wight, 23a, 

 234; at CEningen, 248, 249. 



limestone, 232; formed in 



recent lakes, 326. 



Fuller's earth, 188. 



G. 



Gait, or Folkstone marl, 201. 



Geodes, found in green sand near Sid- 

 mouth, 200. 



Geological map, Plate 6., explained, 10; 

 index, outline of, 371. 



Geology, advantages to be derived from 

 the study of, 365; Professor Sedg- 

 wick's remarks on the study of, 366. 



Gergovia, bones of land animals found 

 there in freshwater limestone, 229. 



Glentilt, in Scotland, peculiarities of 

 granite there, 64. 



Globular structture, 40 ; in basalt, ex- 

 plained, 146. 



GicmVs Causeway, 141 



Gneiss, a schistose or slaty granite, 64 ; 

 alternates with massive granite, ib.; 

 Chap. VI. 71 ; called secondary gran- 

 ite by some geologists, ib. ; has often 

 a waved form, 72 ; contains most of 

 the metallic ores, ib.; the principal 

 rock formation of Sweden, ib. ; not a 

 stratified rock, ib. 



Gold, native, found in England and Ire- 

 land, 298. 



mines in Carolina, 297. 



Gordal Sear 93. 



G/anitveind of Saussure an incipient 

 gneiss, 71. 



Granite,^ Chap. V. ; composition of, 57 ; 

 sometimes globular, 59 ; vertical beds 

 of, 59 ; Mont Blanc, the highest point 

 at which it is known to occur, ib. ; lo- 

 calities of, 62; at a lower level in 

 North America than in Europe, ib. ; 

 identity with sienite maintained by 

 Dr. Mac Culloch, 66; relative ages 



